question about UUID collision and ChezScheme correctness

[symingz]

Hello, I noticed that ChezScheme made use of UUID extensively internally. I'm curious to know, is it possible (however low the probability) for ChezScheme to malfunction in the event of an UUID collision?

[mnieper]

The probability is much lower than another Cretaceous–Paleogene extinction event, but mathematically it is non-zero. If a collision happens, Chez Scheme can malfunction; for example, generate-temporaries guarantees fresh identifiers each time and macros using this form rely on this fact, e.g. here:

ChezScheme/s/syntax.ss

Line 8318 in dde71a0

(with-syntax ([(p ...) (generate-temporaries #'(x ...))]

Fortunately, we won't live long enough to observe such a collision and malfunction.